- First you gotta make a half square triangle. (There are 20 tutorials online for doing this. Pick one you like.) But be smart and make it too big. That'll give you room to fix it. Then put the TSU Ruler on top. It's got lines for whatever size block you want from 1" to 6.5". Find that line and scoot it over your block until it matches with your diagonal seam. My block is 4.5". (Sorry for blurry.)
- Hold down the ruler and cut off whatever sticks out. In this case it's the dark blue edges.
- Flip around your square and replace the TSU Ruler with the same line on the diagonal seam.
- Cut off whatever sticks out--now it's the cream fabric.
- Admire your near-perfect half square triangle, or squiangle, if you prefer.
- Make 674 more and assemble into a lovely king-size quilt. Ice your hand.
1 hour ago